Cold radiators - Baxi back boiler gravity fed system

[hands2bfree]

Long story ill try to supply all the info:

moved into house - evident the heating had never been touched since 5 years ago when a new baxi back oiler was installed, mix ages of rads throughout the house.

the system is gravity fed

pump working but not sure how to bleed- do i just remove the disc cover?

first, down stairs rad in living room never got hot
second, box room was cold - rad bleed valve was rounded over - so could not bleed system
third, conservatory rad cold.
fourth, dining room and 2 bedrooms rad hot

I replaced the box room rad, but system still same after bleeding

I emptied the system through and filled up + inhibitor.

Still same issue with rads, but with knocking = plumber recommended a solution that that disperses air locks.

poured the solution in and then all rads went cold.

tried heating non stop on high for a few days but no results.

i emptied the system and put clean water in, but still no warm rads.

but i hear knocking again.

any ideas would be welome

Read more:Cold radiators - DIYnot.com - DIY and Home Improvement​

 

[jtsplumbing]

You seem to have a air lock on system or a faulty pump, is pump getting very hot ?? if so remove large center screw from pump, put in small screw driver , you will feel if pump is working, try this first and see what happens.

 

[hands2bfree]

Thanks for replying - yes the pump is rotating, not too hot - touchable.

 

[jtsplumbing]

Ok motor is working but its poss that impeller has snaped off, if its an old pump may be an idea to replace this first.

 

[hands2bfree]

Ok, if i remove the pump is it possible to inspect to see if impeller is intact?

 

[jtsplumbing]

yes you will see impeller in pump try to turn it with screw driver or switch it on if it runns OK make sure its faceing right way .

 

[hands2bfree]

Thanks, ill give it ago latter this evening when im home.

if the pump is ok, are there any other things i can do?

 

[jtsplumbing]

You may just have a bad air lock in system , has it ever work`d ? what area are you in ?? may be one of the guys on here could call round and have a look for you

 

[hands2bfree]

i have only been in the house a 2 years, never worked properly.
i live in Southend on Sea, Essex.

 

[jtsplumbing]

To far for me ! deep depths of Devon, may be one of the Essex guys can help ! do they still were white stiletto`s in Essex ! I am talking about the gas engineers !!:49: